An international team of astronomers discovered a rectangular‑shaped galaxy within a group of 250 galaxies some 70 million light years away.

Alister Graham from Swinburne University of Technology said the rare rectangular-shaped galaxy was a very unusual object. “It’s one of those things that just makes you smile because it shouldn’t exist, or rather you don’t expect it to exist. It’s a little like the precarious Leaning Tower of Pisa or the discovery of some exotic new species which at first glance appears to defy the laws of nature.”

The unusually shaped galaxy was detected in a wide field-of-view image taken with the Japanese Subaru Telescope for an unrelated program by Swinburne astrophysicist Dr Lee Spitler.The astronomers suspect it is unlikely that this galaxy is shaped like a cube. Instead, they believe that it may resemble an inflated disc seen side on, like a short cylinder.

Support for this scenario comes from observations with the giant Keck Telescope in Hawaii, which revealed a rapidly spinning, thin disc with a side‑on orientation lurking at the centre of the galaxy.

Despite its apparent uniqueness, partly due to its chance orientation, the astronomers have managed to glean useful information for modelling other galaxies. While the outer boxy shape is somewhat reminiscent of galaxy merger simulations which don’t involve the production of new stars, the disc-like structure is comparable with merger simulations involving star formation. The results will be published in The Astrophysical Journal.